A few years ago, I read that there were 2 theories about the origin of
the australian aborigines to explain their distinct features.
Either they had been isolated from other humans and thus evolved
separately after the australian continent came into existence OR they
had a distinct genetic background meaning that they would be the only
humans on the planet who are not homo sapiens sapiens, but a small
terminal parallel branch (but by no means inferior) in the evolution tree.

Questions:
1- Is my understanding correct ? is there such a controversy ?
2- Has this issue been resolved with recent advances in genetic mapping of
human populations ?